PARENT SESSION
Gene Regulation & Function

CHARACTERIZATION OF THE PORCINE AMPHIREGULIN GENE.

Kim, Jong¹, Vallet, Jeffrey¹, Christenson, Ronald¹, ¹

ABSTRACT- Uterine capacity is a component trait contributing to litter size in swine. Gene mapping analyses revealed a quantitative trait locus (QTL) for uterine capacity on chromosome 8. The amphiregulin gene has been mapped to chromosome 8 at 65 cM, close to the previously identified uterine capacity QTL, and is expressed by uterine endometrium during pregnancy. The objective of this study was to characterize the porcine amphiregulin gene in order to begin to understand the control of transcription of the gene in endometrium. A clone containing the amphiregulin gene isolated from a porcine bacteriophage artificial chromosome (BAC) genomic library was digested with PstI, and fragments containing portions of the gene were subcloned. Sequencing of these clones, along with cloning and sequencing of PCR products using the BAC clone as template, revealed that the gene consists of 6 exons and 5 introns. The sizes and boundaries of the exons were similar to those of human amphiregulin, except that exon 2 of the human amphiregulin gene is 18 bp longer than that of porcine amphiregulin. The 3174 bp region upstream of the transcription start site was conserved (69% identity) compared to the human amphiregulin gene. Signal scan analysis along with alignment of this region with the upstream region of the human amphiregulin gene revealed a conserved TATA box located at -28 bp from the transcription start site. Also, the conserved palindromic sequence TGACGTCA, which is similar to AP-1 and/or cyclic AMP-responsive element sites, was located at -64 bp from the transcription start site. A second palindromic site containing potential conjoined enhancer/C-myb/enhancer binding sites was located at -2098 bp. These and other conserved binding sites for transcription factors may be important for the regulation of porcine amphiregulin gene expression in endometrium. Understanding the control of the amphiregulin gene in endometrium may lead to strategies to improve litter size in swine.

KEY WORDS: uterine capacity, litter size, gene expression, transcription factors